Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-09-27
2003-07-15
Reddick, Judy M. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C523S201000, C524S503000, C526S201000, C526S202000, C526S269000, C526S270000, C526S314000
Reexamination Certificate
active
06593412
ABSTRACT:
BACKGROUND OF THE INVENTION
Limited information exists in the literature regarding the copolymerization of vinyl ethylene carbonate (VEC), especially the formation of emulsion copolymers incorporating VEC. “Synthesis of cyclic carbonate functional polymers,” by Dean C. Webster and Allen L. Crain,
ACS Symposium Series
704, American Chemical Society, 1998, Chapter 21, pages 303 to 320, contains a review of VEC copolymerization. Emulsion copolymerization of VEC with vinyl acetate and butyl acrylate is reported. Up to 15% VEC was incorporated into vinyl acetate/butyl acrylate latexes containing 20% butyl acrylate and 65 to 78% vinyl acetate.
U.S. Pat. No. 2,511,942 (Prichard, 1950) discloses the preparation of VEC and indicates that it can be copolymerized with other unsaturated monomers, such as ethylene, isobutylene, styrene, vinyl chloride, vinyl acetate, and vinyl acrylics. Emulsion copolymerization is not disclosed.
“Polymerization of vinyl ethylene carbonate and reaction of the formed polymer,” by Teruzo Asahara, et al. (
Production Research
, Vol.25, No.7, 1973), discloses free radical polymerization of VEC with each of styrene, vinyl acetate, and maleic anhydride.
U.S. Pat. No. 5,567,527 (Webster et al., 1996) discloses carbonate functional copolymers formed from the free-radical copolymerization of VEC with other ethylenically unsaturated monomers such as acrylic and methacrylic acids and their esters, styrene-type monomers, vinyl chloride, vinyl acetate, allyl compounds, and acrylamide. The copolymers can be crosslinked with multifunctional primary amines and are reported to be useful in two-component crosslinked or thermosetting organic coatings. Emulsion copolymers are formed in the presence of surfactants and comprise water and a curable acrylic copolymer containing 1 to 50 wt % VEC, based on the total weight of monomers. An example shows the formation of an emulsion copolymer of VEC with vinyl acetate and butyl acrylate.
WO 99/62970 (Webster et al., 1999) discloses a process for the free radical copolymerization of VEC with other unsaturated monomers. Examples show the emulsion polymerization of VEC with vinyl acetate and butyl acrylate to form copolymers in which the ratio of VEC to other monomers is 25:75.
U.S. Pat. No. 4,263,418 (Steffen et al., 1981) discloses graft copolymers consisting of 10 to 80 wt % ethylene/vinyl ester copolymer containing 1 to 75 wt % vinyl ester; and 90 to 20 wt % of a grafted monomer mixture consisting essentially of: 5 to 50 wt % acrylonitrile and/or methacrylonitrile; 95 to 50 wt % of one or more aromatic monovinyl compound; and small quantities (0.01 to 0.5% by weight) of copolymerized allyl compound, such as VEC or diallyl carbonate.
WO 99/62968 (Mackenzie, et al., 1999) discloses supported group 8-10 transition metal olefin polymerization catalysts. Solution polymerization of 96.5 to 95.5 wt % ethylene and 3.5 to 4.5 wt % VEC is shown in examples 77 and 78.
BRIEF SUMMARY OF THE INVENTION
This invention is directed to aqueous based emulsion copolymers containing vinyl ethylene carbonate (VEC), ethylene and at least one other ethylenically unsaturated monomer. One embodiment of this invention is the incorporation of VEC into vinyl acetate-ethylene emulsion copolymers. Another embodiment is aqueous based poly(vinyl alcohol)-containing emulsion copolymers that are formed by copolymerizing VEC with vinyl acetate and, optionally, another ethylenically unsaturated monomer in the presence of poly(vinyl alcohol). The aqueous based poly(vinyl alcohol)-containing emulsion copolymer can be a grafted poly(vinyl alcohol) polymer. Yet another embodiment of this invention is the use of emulsion copolymers of VEC and other ethylenically unsaturated monomers such as vinyl acetate or vinyl acrylic compounds in adhesive applications, such as wood glue.
There are several advantages to incorporating VEC into emulsion copolymers.
For example:
the emulsion copolymers exhibit good adhesive properties;
the T
g
(glass transition temperature) of the emulsion copolymer can be increased;
a two stage emulsion polymerization can be used to produce VEC-vinyl acetate-ethylene emulsion copolymers with a high ethylene content; and
incorporation of other ethylenically unsaturated monomers into poly(vinyl alcohol)-containing polymers, can be enhanced.
The VEC emulsion copolymers of this invention can be used in a variety of applications, such as adhesives, coatings, and nonwovens and paper applications.
DETAILED DESCRIPTION OF THE INVENTION
VEC can be emulsion copolymerized with vinyl acetate and a variety of other ethylenically unsaturated monomers using standard emulsion polymerization procedures as practiced in the industry.
The emulsion copolymers comprise 2 to 30 wt % of VEC, 2 to 50 wt % ethylene, and 20 to 96 wt % of one or more additional ethylenically unsaturated copolymerizable monomer, based on the total monomers.
Suitable ethylenically unsaturated monomers which can be employed for emulsion copolymerization with VEC and ethylene include, but are not limited to, vinyl acetate, vinyl chloride, C
1
to C
12
alkyl acrylates, and C
1
to C
12
alkyl methacrylates, such as ethyl methacrylate, methyl methacrylate, 2-ethylhexyl acrylate, butyl acrylate, propyl acrylate, ethyl acrylate, methyl acrylate, hydroxyethyl acrylate, and hydroxypropyl acrylate, and mixtures thereof.
It has been found that ethylene cannot be emulsion copolymerized with VEC in the absence of another ethylenically saturated monomer such as vinyl acetate. It has also been found that incorporation of ethylene is retarded in the preparation of copolymer of ethylene with VEC and another ethylenically unsaturated monomer, using typical emulsion polymerization techniques. However, unexpectedly it has been found that use of a two stage polymerization process is effective in making copolymers containing the amounts of monomers described above.
In the two stage emulsion polymerization, about 30 to 70% of the total monomers (containing about 50% of an ethylenically unsaturated other than ethylene or VEC, and about 50% ethylene) can be reacted in one stage and about 70 to 30% of the total monomers (containing about 30% VEC and about 70% of the other ethylenically unsaturated monomer) can be reacted in another stage using well known emulsion polymerization methods. The order of the above reactions can be reversed, provided that the second reaction is carried out in the presence of the product of the first reaction.
Polymerization can be initiated by thermal initiators or by a redox system. A thermal initiator is typically used at temperatures at or above about 70° C. Redox systems are typically used at temperatures below about 70° C. The amount of thermal initiator used in the process is 0.1 to 3 wt %, preferably about 0.5 wt %, based on total monomers. Thermal initiators are well known in the emulsion polymer art and include, for example, ammonium persulfate, sodium persulfate, and the like. The amount of oxidizing and reducing agent in the redox system is about 0.1 to 3 wt %. Any suitable redox system known in the art can be used; for example, the reducing agent can be a bisulfite, a sulfoxylate, ascorbic acid, erythorbic acid, and the like. The oxidizing agent can include hydrogen peroxide, organic peroxide such as t-butyl peroxide, persulfates, and the like.
In addition to the above reaction conditions and components, the polymer latex may be stabilized with conventional emulsifiers or surfactants, and protective colloids.
The protective colloid can be poly(vinyl alcohol) in amounts of about 0.5 to 5 wt %, preferably 2 to 5 wt %, based on monomers. The poly(vinyl alcohol) can be 75 to 99+ mole % hydrolyzed, preferably 85 to 90 mole % hydrolyzed, with a degree of polymerization ranging from 50 to 3000; preferably, 100 to 1500. The degree of polymerization of the poly(vinyl alcohol) affects the viscosity of the emulsion product; i.e., as degree of polymerization increases, viscosity of the emulsion product increases.
The surfactant or emulsifier can be used at a level of about 1 to 4 wt %, pref
Bott Richard Henry
Rabasco John Joseph
Smith Carrington Duane
Air Products Polymers, L.P.
Bongiorno Mary E.
Reddick Judy M.
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